package com.luoy;



import org.apache.tomcat.util.codec.binary.Base64;

import javax.crypto.Cipher;
import java.security.*;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;


public class RSACoder {
    public static final String KEY_ALGORITHM = "RSA";
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

    private static final String PUBLIC_KEY = "RSAPublicKey";
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    public static byte[] decryptBASE64(String key) {
        return Base64.decodeBase64 (key);
    }

    public static String encryptBASE64(byte[] bytes) {
        return Base64.encodeBase64String (bytes);
    }

    /**
     * 用私钥对信息生成数字签名
     *
     * @param data       加密数据
     * @param privateKey 私钥
     * @return
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        // 解密由base64编码的私钥
        byte[] keyBytes = decryptBASE64 (privateKey);
        // 构造PKCS8EncodedKeySpec对象
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec (keyBytes);
        // KEY_ALGORITHM 指定的加密算法
        KeyFactory keyFactory = KeyFactory.getInstance (KEY_ALGORITHM);
        // 取私钥匙对象
        PrivateKey priKey = keyFactory.generatePrivate (pkcs8KeySpec);
        // 用私钥对信息生成数字签名
        Signature signature = Signature.getInstance (SIGNATURE_ALGORITHM);
        signature.initSign (priKey);
        signature.update (data);
        return encryptBASE64 (signature.sign ());
    }



    /**
     * 校验数字签名
     *
     * @param data      加密数据
     * @param publicKey 公钥
     * @param sign      数字签名
     * @return 校验成功返回true 失败返回false
     * @throws Exception
     */
    public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
        // 解密由base64编码的公钥
        byte[] keyBytes = decryptBASE64 (publicKey);
        // 构造X509EncodedKeySpec对象
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec (keyBytes);
        // KEY_ALGORITHM 指定的加密算法
        KeyFactory keyFactory = KeyFactory.getInstance (KEY_ALGORITHM);
        // 取公钥匙对象
        PublicKey pubKey = keyFactory.generatePublic (keySpec);
        Signature signature = Signature.getInstance (SIGNATURE_ALGORITHM);
        signature.initVerify (pubKey);
        signature.update (data);
        // 验证签名是否正常
        return signature.verify (decryptBASE64 (sign));
    }

    public static byte[] decryptByPrivateKey(byte[] data, String key) throws Exception {
        // 对密钥解密
        byte[] keyBytes = decryptBASE64 (key);
        // 取得私钥
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec (keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance (KEY_ALGORITHM);
        Key privateKey = keyFactory.generatePrivate (pkcs8KeySpec);
        // 对数据解密
        Cipher cipher = Cipher.getInstance (keyFactory.getAlgorithm ());
        cipher.init (Cipher.DECRYPT_MODE, privateKey);
        return cipher.doFinal (data);
    }

    /**
     * 解密<br>
     * 用私钥解密
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(String data, String key) throws Exception {
        return decryptByPrivateKey (decryptBASE64 (data), key);
    }
    public static String directDecryptByPriKeyInSugon(String data, String privateKey) throws Exception {
        byte[] bytes = decryptByPrivateKey (decryptBASE64 (data), privateKey);
        return new String (bytes);
    }

    /**
     * 解密<br>
     * 用私钥解密
     *
     * @param data
     * @param publicKey
     * @return
     * @throws Exception
     */
//    public static String decryptByPublicKeyInSugon(String data, String publicKey) throws Exception {
//        String privateKey = InfrastructureController.keys.get (publicKey);
//        InfrastructureController.keys.remove (publicKey);
//        byte[] bytes = decryptByPrivateKey (decryptBASE64 (data), privateKey);
//        return new String (bytes);
//    }
//
//    public static String directDecryptByPubKeyInSugon(String data, String publicKey) throws Exception {
//        byte[] bytes = decryptByPublicKey (decryptBASE64 (data), publicKey);
//        return new String (bytes);
//    }
//
//    public static List<String> decryptByPublicKeyInSugon(List<String> datas, String publicKey) throws Exception {
//        String privateKey = InfrastructureController.keys.get(publicKey);
//        InfrastructureController.keys.remove (publicKey);
//        List<String> returnPasswds = new ArrayList<> ();
//        for (String s : datas) {
//            returnPasswds.add (new String (decryptByPrivateKey (decryptBASE64 (s), privateKey)));
//        }
//        return returnPasswds;
//    }

    /**
     * 解密<br>
     * 用公钥解密
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] data, String key) throws Exception {
        // 对密钥解密
        byte[] keyBytes = decryptBASE64 (key);
        // 取得公钥
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec (keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance (KEY_ALGORITHM);
        Key publicKey = keyFactory.generatePublic (x509KeySpec);
        // 对数据解密
        Cipher cipher = Cipher.getInstance (keyFactory.getAlgorithm ());
        cipher.init (Cipher.DECRYPT_MODE, publicKey);
        return cipher.doFinal (data);
    }

    /**
     * 加密<br>
     * 用公钥加密
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(String data, String key) throws Exception {
        // 对公钥解密
        byte[] keyBytes = decryptBASE64 (key);
        // 取得公钥
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec (keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance (KEY_ALGORITHM);
        Key publicKey = keyFactory.generatePublic (x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance (keyFactory.getAlgorithm ());
        cipher.init (Cipher.ENCRYPT_MODE, publicKey);
        return cipher.doFinal (data.getBytes ());
    }

    /**
     * 加密<br>
     * 用私钥加密
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String key) throws Exception {
        // 对密钥解密
        byte[] keyBytes = decryptBASE64 (key);
        // 取得私钥
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec (keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance (KEY_ALGORITHM);
        Key privateKey = keyFactory.generatePrivate (pkcs8KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance (keyFactory.getAlgorithm ());
        cipher.init (Cipher.ENCRYPT_MODE, privateKey);
        return cipher.doFinal (data);
    }

    /**
     * 取得私钥
     *
     * @param keyMap
     * @return
     * @throws 2
     */
    public static String getPrivateKey(Map<String, Key> keyMap) throws Exception {
        Key key = (Key) keyMap.get (PRIVATE_KEY);
        return encryptBASE64 (key.getEncoded ());
    }

    /**
     * 取得公钥
     *
     * @param keyMap
     * @return
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Key> keyMap) throws Exception {
        Key key = keyMap.get (PUBLIC_KEY);
        return encryptBASE64 (key.getEncoded ());
    }

    /**
     * 初始化密钥
     *
     * @return
     * @throws Exception
     */
    public static Map<String, Key> initKey() throws Exception {
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance (KEY_ALGORITHM);
        keyPairGen.initialize (1024);
        KeyPair keyPair = keyPairGen.generateKeyPair ();
        Map<String, Key> keyMap = new HashMap (2);
        keyMap.put (PUBLIC_KEY, keyPair.getPublic ());// 公钥
        keyMap.put (PRIVATE_KEY, keyPair.getPrivate ());// 私钥
        return keyMap;
    }

    public static void main(String[] args) throws Exception {
        Map<String, Key> keyMap = RSACoder.initKey();
        String publicKey = RSACoder.getPublicKey(keyMap);
        String privateKey = RSACoder.getPrivateKey(keyMap);
//        System.err.println("公钥: \n\r" + publicKey);
//        System.err.println("私钥： \n\r" + privateKey);
//        System.err.println("公钥加密——私钥解密");
//        String inputStr = "dounine";
//        byte[] encodedData = RSACoder.encryptByPublicKey(inputStr, publicKey);
//        String s = Base64.encodeBase64String (encodedData);
//        System.out.println (s);
//        byte[] decodedData = RSACoder.decryptByPrivateKey(encodedData,
//                privateKey);
//        String outputStr = new String(decodedData);
//        System.err.println("加密前: " + inputStr + "\n\r" + "解密后: " + outputStr);

//        byte[] s = RSACoder.encryptByPrivateKey("douhuanjua".getBytes (), privateKey);
//        String s1 = Base64.encodeBase64String(s);
//        String  ret =  RSACoder.directDecryptByPubKeyInSugon (s1, publicKey);
//        System.out.println (ret);
//
//        byte[] luos = RSACoder.encryptByPublicKey("luo", publicKey);
//        String s3 = Base64.encodeBase64String(luos);
//
//        byte[] bytes = RSACoder.decryptByPrivateKey(s3, privateKey);
//
//        String s2 = new String(bytes);
//        System.out.println("pwd"+s2);
    }
}
